Electro-analytical system for monitoring total organic carbon in a water source

Abstract

An automated total organic carbon analyzer is described. Embodiments of the system include two features, namely the development of a selective oxidation reactor to oxidize organic contaminants to their corresponding organic acids, and the measurement of the organic acids individually by chain length using an electroanalytical detector. Combining this electroanalytical approach with sequential detection capabilities (such as spectrophotometry) can expand the instrument capabilities by providing organic contaminant speciation. The described reactor performs selective oxidation of organic carbon to organic acids followed by complexation with a proprietary ligand, then selective detection using electroanalytical accumulation and desorption of organic acids performed at an electrode surface.

What is claimed: 
     
       1. A method of treating a water supply, the method comprising:
 introducing an aqueous influent stream into an electrochemical reactor, wherein the aqueous stream comprises at least one organic contaminant; 
 oxidizing at least one organic contaminant to an organic acid using a controller operably connected to the reactor, wherein the controller is configured substantially prevent oxidation to carbon dioxide; 
 identifying at least one organic acid using an electroanalytical method, wherein the electroanalytical method for identifying the organic acid comprises complexing the organic acid with a ligand to form an analyte, accumulating the analyte onto the surface of an electrode, applying a current to the electrode to cause desorption of the analyte, and identifying the type of organic acid analyte based on a measure electromotive potential; 
 determining the concentration of at least one organic acid using an electroanalytical method, wherein the electroanalytical method for determining the concentration of at least one organic acid comprises analyzing the current applied to cause desorption of the analyte; 
 estimating the concentration of total organic carbon in the aqueous influent stream based on the determined concentration of at least one organic acid species. 
 
     
     
       2. The method of  claim 1 , further comprising maintaining the temperature of the reactor between about 150° C. and about 250° C. 
     
     
       3. The method of  claim 1 , wherein reaction kinetics are monitored at the surface of an electrode by voltammetric detection. 
     
     
       4. The method of  claim 1  wherein the ligand comprises a single amine functional group. 
     
     
       5. The method of  claim 1 , further comprising differentiating at least one organic acid using spectrophotometry. 
     
     
       6. The method of  claim 5 , wherein the spectrophotometry comprises IR spectrophotometry or UV-vis spectroscopy or a combination thereof. 
     
     
       7. The method of  claim 1 , further comprising analyzing the current applied to the electrode to cause desorption of the analyte to at least partially determine chemical structure of the analyte. 
     
     
       8. The method of  claim 1 , wherein the aqueous influent stream comprises a substantially constant level of dissolved carbon dioxide. 
     
     
       9. The method of  claim 1 , wherein the at least one organic acid contaminant comprises volatile organic compounds.